Filter cloth



June w. H. BAGHELD'OR ET AL ,573

FILTER CLOTH Filed July 29, 1929 Patented Jtme' 23, 1931 UNITED STATES-PATENT oer-Ica- WTLLIAI H. BACHELDOR AND WILLIAM E. WOOD, OI 700D RIVER, ILLDIOIS, A8-

SIGNOBS TO STANDARD OIL GOIPANY,'OI' WRITING, INDIANA, A. GOBPORATION OF INDIANA This invention relates to filterin cloth which is employed as the filterin me iumin filters of the pressure type, an is particu larly adapted for the filtration of hot petro- 5 leumtars and residues.

The invention will readily be understood 'from the following description in con unc- I 7 tion with the accompanying drawing, which is a perspective view of a piece of cloth embodying the present inventlon, the outer edges of which are'partially unwoven, while" fabric strands 12 which are twisted around The graphite surface of the cloth is faced 4;. A fabric filter media for filtering highly Y a strand of wire 13 formed by two metal wires 14 which are twisted or wound toether. The strands 12 are made of Ion fibred Canadian asbestos and cotton. Each strand 12contains at least 95%of the Canadian asbestos and not more than 5% of the cotton. It is referred that the cotton content not exceed 3%. p 0 The cloth has one of its surfacescoated with graphite,- a portion of such coating being shown at 15. The'graphite may be applied in any suitable way, for example, by rubbing or b applying a suspens10n of graphite with rushes,.or the like.

1n ressure filters of the well known Kelly or weetland types. In the former, the cloth constitutes the outer coverin for a hollow leaf-like element which is paced within a closed tank or receptacle into which the liquid to be filtered is fed. The liquid flows through the filter cloth and into the interior of the leaf, the cloth functioning to filter from the liquid an of the solid matter entrained therein. e filtrate is discharged from the interior of the leaf by means of a suitable conduit which communicates with the exterior of the tank or receptacle.

The cloth is particularly adapted to be used 7 rmrna cnorn Applicationfiled m 29,

Serial No. 882,057.

outwardly and comes into direct contact with the hot petroleum tars to be filtered. Since these tars are too viscous'to be successfully filtered at ordinary temperatures, it is neces sary that they bepassed through the filter while highl heated. The solid matter filtered from t e tar accumulates upon the outer surface of the'cloth in the form of a tarry asphaltic cake. The filter must be shut down from time to time so that this cake may be removed. v

The filter cloth of the resent invention is particularly adapted to employed as the filtering medium for such hot'petroleum'tars. It has been found that the fabric is longlived and that it has a high efiiciency, in that large volumes of hot tar may be passed through it, while the filtrate produced is of high quality. The graphite functions to prolong the life of the filter cloth, and at the same time facilitates separating the tarry asphaltic filter cake from the cloth.

The foregoing-detailed description has been g given for clearness of'understanding only claims should be construed as broadly as permissible, in view of the prior art. We claim:

1. A filter cloth for filtering highly heated viscous hydrocarbon oils in pressure filters which comprises interwoven threads each thread being formed of asbestos fibres and not more than 5% of cotton fibres intermingled therewith.

2. A filter cloth for filtering highly heated viscous hydrocarbon oils in pressure filters which comprises interwoven threads each thread being formed of asbestos fibres and not more than 5% of cotton fibres intermingled therewith, said threads having a wire center.

3. A filter media for filtering highly heated viscous hydrocarbon oils in pressure filters which comprises a cloth formed of closely interwoven threads, said threads being formed of asbestos fibres and not more than 5% of cotton fibres intermingled therewith, said cloth having its filtering surface coated with. graphite.

heated viscous hydrocarbon oils in pressure leaf filters which comprises a cloth formed of closely interwoven threads, said threads being formed of strands each strand comprising long-fibered asbestos and not more than 5% cotton intermingled therewith, said strands being wrapped around a twisted metal wire.

5. A fabric filter media for filtering highly heated viscous hydrocarbon oils in pressure leaf filters which comprises a cloth formed of closely interwoven threads, said threads being formed of strands each strand comprising long-fibered asbestos and not more than 3% cotton intermingled therewith, said strands being wrapped around a strand of a plurality of twisted metal wires, said cloth having its filtering surface coated with graphite.

6. A filter cloth for filtering highly heated viscous hydrocarbon oils in pressure filters which comprises interwoven threads, each of which threads consists of asbestos fibres and not more than 5% of intermingled cotton fibres before the-cloth is subjected to high temperature conditions.

7. A filter cloth for filtering highly heated viscous hydrocarbon oils in pressurefilters which comprises interwoven threads, each of which threads consists of asbestos fibres and not more than 5% of intermingled cotton 1 fibres before the cloth is subjected to high temperature conditions suflicient to eflect charring of the cotton.

WILLIAM H. BACHELDOR. WILLIAM E. WOOD. 

